At least 15 King County Superior Court cases and two federal cases could be in trouble because of an investigation into the credibility of Seattle police officers Gregory Neubert and Michael Tietjen. One King County case already has been dismissed.

Letters about the investigation have been sent to defense attorneys in the following cases:

• State v. Julian Patton: On Dec. 10, 2006, Neubert and Tietjen alleged, they used a telescope to observe Patton, a convicted robber, stash a handgun in the trunk of his car. He also allegedly had Vicodin, a prescription pain medicine, in his pocket.

• State v. Demetrius Hoskins: On June 2, 2006, Tietjen and another officer alleged, they caught Hoskins with a small amount of crack in Pioneer Square.

• State v. James Dobson (two cases): On June 13, 2006, Neubert and another officer alleged, they found about 18 grams of crack in Dobson’s car near Third Avenue and Blanchard Street. Then, on June 18, Neubert and another officer alleged, they again caught Dobson with a small amount of crack.

• State v. Terry Cameron: On June 17, 2006, Neubert and other officers observed Cameron allegedly selling crack to another man at Second and Pike.

• State v. Precious Reed: On Oct. 4, 2006, Tietjen and other officers allegedly observed Reed and two other men dealing crack at Second and Pike.

• State v. Latena Bacani: On Nov. 2, 2006, Neubert and Tietjen alleged, they observed Bacani selling crack in an alley east of Second and Pike.

• State v. George Troy Patterson: On Jan. 2, 2007, Neubert and Tietjen alleged, they caught Patterson with a small amount of crack at Second and Pike. Charges have been dismissed.

• State v. Milton Rodriguez: On Jan. 27, 2007, Rodriguez, 41, allegedly sold $20 worth of crack to an undercover officer in Belltown.

Federal cases

• U.S. v. Hubert T. Isabel: On July 19, 2006, Neubert and Tietjen alleged, they were arresting suspected drug dealers in a car at Second and Pike when they saw Isabel, a convicted felon, stash a pistol under the seat.

• U.S. v. Tyrone Patin: On Nov. 9, 2005, Neubert and Tietjen stopped Patin on Fourth Avenue because people were complaining that he was dealing drugs.

He was searched and allegedly had crack. Police later searched Patin’s apartment and allegedly turned up 284 grams of crack, about 58 grams of powdered cocaine, 58 grams of black-tar heroin and loaded handguns.

Then, on Jan. 3, 2006, Neubert and Tietjen alleged, they caught Patin with a large amount of crack, cocaine and heroin in a motel room on Aurora Avenue North.